1. Field of the Invention
The present invention relates to an image forming apparatus and more particularly, to an image forming apparatus provided with a nozzle recovery unit on the side thereof opposing the nozzle surface of a recording head.
2. Description of the Related Art
An image forming apparatus based on an inkjet method forms images on recording paper by discharging ink onto recording paper from a recording head. In an image forming apparatus of this kind, in order to clean the nozzles of the recording head and prevent the nozzles from drying out, nozzle recovery processing is carried out whereby, for example, ink is discharged from the nozzles at prescribed time intervals (preliminary discharge), of the nozzles are cleaned by wiping the nozzles with a blade, or the like. This nozzle recovery processing is problematic in that, if the recording head is withdrawn until a region outside the image forming region, then the overall size of the apparatus becomes very large, the time taken to perform maintenance becomes long, and the efficiency of image forming declines. In order to resolve this, technology is known wherein a platen unit and a maintenance unit are provided on a rotating body disposed opposing the recording head (see Japanese Patent Application Publication No. 2001-71521).
More specifically, in the image forming apparatus disclosed in Japanese Patent Application Publication No. 2001-71521, a cap for covering the discharging surface of the recording head, and a blade, or the like, for wiping the nozzles are provided on a rotating body, on the opposite side to a platen unit, and maintenance of the recording had is carried out by causing the rotating body to rotate and making the cap and blade contact the recording head.
However, in the case of full-surface marginless printing for forming an image on the entire surface of the recording paper, ink falling beyond the sides of the recording paper may land on the platen unit, and hence there is a risk that the rear surface of the subsequently conveyed recording paper may become soiled. In order to resolve this situation, technology is known whereby recording is performed by causing a platen made from a plurality of holding plates disposed at prescribed intervals to rotate in synchronization with the conveyance of the recording paper (see Japanese Patent Application Publication No. 2001-80145). In this image forming apparatus, since the platen is hidden on the rear side of the recording paper, full-surface marginless printing can be carried out without causing soiling of the platen by means of ink beyond the edges of the recording paper.
In the image forming apparatus described in Japanese Patent Application Publication No. 2001-80145, however, since the platen is provided on the circumferential face of the rotating body, close contact between the recording paper and the platen cannot be achieved, and waves may arise in the paper, in addition to which, since the surface of the platen supporting the recording paper, which makes contact with the recording paper, is a curved surface, then the distance of flight of the ink ejected from the nozzles of the recording head is not uniform, and hence image quality will decline.